Diversity of Fauna in Crimean Hypersaline Water Bodies

Abstract

On the Crimean peninsula, there are more than 50 hypersaline water bodies, including the Sivash (the Sea of Azov), the largest hypersaline lagoon in the world. Based on the literature and our own long-term research data (2000–2017), a review of the fauna of the hypersaline waters in the Crimea is presented, including 298 species of animals belonging to 8 phyla, 14 classes and 27 orders. The variety of phyla and classes within a particular range of salinity was shown to decrease significantly with an increase in salinity; 8 classes in 3 phyla can withstand salinities above 100 g/L, and only 4 classes (Branchiopoda, Hexanauplia, Ostracoda and Insecta) within 1 phylum (Arthropoda) occur at salinities above 200 g/L. The number of species found in a single sample also decreased with increasing salinity. However, in the range of 50–120 g/L, the number of species was mainly determined by a different set of factors. The abundance of animals in the hypersaline waters of the Crimea can be very high: e.g., Nematoda – up to 1.4∙107 ind./m2, Harpacticoida – up to 3.5∙106 ind./m2, Ostracoda – up to 5.8∙105 ind./m2, and Moina salina – up to 1.3∙106 ind./m3. A characteristic feature of hypersaline water ecosystems is the fact that increases in salinity cause increasing amounts of benthic animals (Chironomidae, Harpacticoida, Ostracoda) to change their habitats from the bottom to the water column. At salinities above 120–150 g/L, there is almost no animal life at the bottom. Most of the species found in shallow hypersaline waters have a resting stage in their life cycle, which ensures their survival in abruptly changing environments, even those in ephemeral water bodies

Keywords

• fauna
• crustaceans
• hypersaline waters
• Crimea